1. Field of the Invention
The present invention relates to an apparatus for the non-contact measurement of the gage of a track comprising two rails having rail heads, which comprises a machine frame equipped with undercarriages supporting the machine frame for mobility on the track and a wheel axle having wheels running on the track rails, and an optical sensor associated with each track rail and affixed to the wheel axle.
2. Description of the Prior Art
U.S. Pat. No. 4,490,038 discloses an apparatus for the non-contact determination of the lateral position of a railroad track with respect to an adjacent track. It uses a distance measuring device comprised of a laser beam emitter and receiver with coincident optical axes for emitting and receiving the laser beam, the axes extending in a transverse plane perpendicular to the track and the axis being pivotal in this plane by a drive. A limit switch is associated with, and actuated by, the measuring device to limit the range of the pivoting movement. As soon as the optical axis is pivoted above the rail head of the adjacent track, the distance measuring value changes abruptly. This sudden jump in the measuring value causes the last measured distance value to be stored and indicated when this sudden jump exceeds a selected mimimum value. At the same time the drive is reversed so that the optical axis is pivoted back towards the foot of the rail until the measured distance value jump is eliminated. In this way, the optical axis of the measuring device constantly senses the range of the rail between the rail web and the upper edge of the rail head. The minimal distance to the rail head is indicated and used for the determination of the lateral position. This apparatus cannot be used to measure the track gage or the camber.
Austrian patent No. 344,773 discloses an apparatus for the optical measurement of a lateral deviation of a rail from the desired line. For this purpose, a receiver and a projector are spaced from each other above each rail. The emitted light is reflected from the inside of the rail head. The two receivers and projectors are arranged on a measuring frame which is supported directly on the bearing boxes of a swivel truck. This apparatus is structurally complex and requires a special structure of the undercarriage.
Austrian patents Nos. 321,346 and 328,489 and U.S. Pat. No. 3,864,039 exemplify other optical track gage measuring apparatus but in none of them is the sensor pivotal by a stepping motor about an axis extending in the longitudinal direction of the machine frame.